It just occurred to me that you were posting about Excel in an Access forum.
To add a button to an Excel worksheet, right click on the top menu, select Controls Toolbar, and then click the button control, and then click the cell. You will have to modify the size of the cell and the button to match each other since the button will just be ON the worksheet, and not IN any cell.
Did that help?
Look it up at: http://wrox.books24x7.com